1. Field of the Invention
The present invention relates to systems and methods for planning and/or adjusting aircraft routes. More particularly, the invention relates to automated systems and methods for planning and/or adjusting aircraft routes based on threats in dynamic simulation and operational environments.
2. Background Information
Militaries around the globe conduct a wide variety of training, simulation, and real-world exercises and missions involving aircraft. Personnel who plan air missions and exercises (e.g., called mission planners or mission controllers) are conventionally responsible for planning and adjusting aircraft flight paths to avoid threats so that aircraft can achieve mission and campaign objectives. Threats can include air-based, ground-based, or sea-based threats and may be man-made or naturally occurring. Typical threats include, for example, surface-to-air missiles (SAMs), enemy aircraft armed with air-to-air missiles (AAMs), mountainous terrain, and severe weather.
Various systems and methods are known in the art for routing and/or rerouting an aircraft to avoid threats. U.S. Pat. No. 4,947,350 discloses a method for determining an optimal route for minimizing the likelihood of an aircraft succumbing to a threat. An initial route is selected having a start point, an end point and a plurality of equal-length straight line segments that interconnect multiple waypoints between the start point and the end point. A routine is then implemented wherein each of the waypoints is then moved incrementally in a given direction, and the kill probability accrued by each line segment connected to a given waypoint is evaluated in turn to determine a position for that waypoint which has the lowest associated kill probability. This routine is continued until all of the waypoints have been moved in the given direction to find the optimal position of all the waypoints, thereby providing an optimized route. The routine is then repeated in the above-described manner except that the waypoints are moved in a direction at an angle (e.g., perpendicular) to the previous given direction of waypoint movement. The routine may be repeated again in the above-described manner, but with the movement of the waypoints in a direction at an angle to the previous waypoint movement (e.g., parallel to the first waypoint movement).
U.S. Pat. No. 4,812,990 discloses a method for determining the optimal path of an aircraft between a first point and a second point such that the aircraft heading at the second point is within preselected minimum and maximum heading limits. A two-dimensional reference grid is defined wherein the first point is disposed in the center cell of the first column (or “first rank”) of the grid and the second point is adjacent to the center cell of the last column of the grid. The possible flight paths between the first and second points are determined, and the path of minimum cost is selected as the optimal path. The possible flight paths are constructed by identifying the possible connections between cells in the last column and the second point and then between each pair of adjacent columns, working backward from the last column to the first point, which is located in the first column. A possible connection is deemed to exist when the aircraft can fly from one point to another point and arrive at that other point within particular heading limits without exceeding the predetermined maximum lateral acceleration of the aircraft. Corresponding heading limits are determined for each connection, and all possible flight paths are examined, consistent with the preselected heading limits at the second point (e.g., the final target area) and the maximum lateral acceleration allowed for the aircraft.
U.S. Pat. No. 6,546,338 discloses a method for preparing an avoidance path in a horizontal plane so that an aircraft can resolve a conflicting route with another aircraft that involves a risk of collision occurring within 5 to 10 minutes, wherein the avoidance path minimizes the negative effects of the resultant route diversion on the flight plan of the aircraft. The threatening aircraft first takes an evasive maneuver with an initial heading relative to the threatened aircraft which is tangential, on one side or the other, to the edges of a circle of protection plotted around the threatened aircraft, wherein the radius of the circle of protection is equal to a minimum permitted separation distance. At a suitable point, the threatening aircraft then changes its heading to “home in” on the initial route. The preparation of the avoidance path can be implemented by a flight management computer, and after acceptance by the aircraft crew, the flight management computer ensures that the avoidance path is implemented by the automatic pilot.
U.S. Pat. No. 5,631,640 discloses a computer-based method wherein a previously unknown threat is detected, and a determination is made as to whether the aircraft's planned route intersects intervisibility with the treat (i.e., will make the aircraft visible to the threat). If not, the planned route is maintained. Otherwise, the aircraft route is changed depending on how far the intersection of intervisibility is from the aircraft. A route change is automatically made if the intersection is less than a predetermined distance. If the intersection is greater than the predetermined distance, the aircraft operator is notified, and the severity of the threat is checked against possible altitudes at which the aircraft is permitted to fly to determine if the planned route may be maintained at a different acceptable altitude. If a different acceptable altitude is available, the aircraft operator can maintain the planned route at the new altitude or choose the route change, such that the operator can manually respond to a threat where doing so does not endanger the aircraft.
U.S. Pat. No. 6,334,344 discloses a process for reconfiguring trajectories of airborne vehicles in real time to adapt a mission to a new situation that has arisen through the occurrence of a disrupting event. The process updates real-time context data in view of the occurrence of the disrupting event and analyzes the new real-time context to select a predefined method chosen from a set of different predefined methods stored in memory for determining a new trajectory. Each of the predefined methods directly translates operational strategies customarily employed by aircrew in a given real-time context to determine a new trajectory which best suits the current real-time context. The process executes the selected predefined method, which determines a new trajectory according to the mission data and the real-time context, and displays the new trajectory on a display, overlayed on the current trajectory. If the pilot of the airborne vehicle validates the new trajectory, the process transmits the information of this new trajectory to an automatic pilot device.
U.S. Pat. No. 6,424,889 discloses a method for generating a horizontal path for the avoidance of danger zones for an aircraft. The contours of each danger zone are modeled by a succession of connected segments. Two homing circles and two capture circles are determined, which pass respectively through the initial point and final point, are tangential respectively to the initial route and to the final route, and have respectively the initial and final turning radius of the aircraft. Tangents both to the homing circles or the capture circles and to the contour of each danger zone are determined. From these tangents, pairs of tangents to a homing circle and to a capture circle are identified that avoid danger zones are identified, thereby providing possible path skeletons connecting a homing circle to a capture circle. The shortest of the path skeletons is selected, and then the selected skeleton path is further optimized.
The present inventors have recognized a need for an automated system and method to aid mission planners in air operation centers (AOCs) to perform simultaneous rerouting of multiple aircraft on multiple flight paths, while taking into account changing threats, in order to achieve the objectives of multiple missions. Conventional automated techniques and tools are insufficient to process routing and/or rerouting for large numbers of aircraft and missions (e.g., thousands of missions) that might be controlled by an AOC. Currently, missions are handled among a large number of human mission planners, who must monitor current status of the aircraft and its mission, the intended goals, and the changing threats that might prevent those missions from being successful. Additionally, processing air tasking orders into suitable simulation orders is tedious and time-consuming for the mission planners and is prone to errors. The present inventors have recognized a need to reduce the manpower that is associated with processing routing and/or rerouting for large numbers of aircraft and missions in simulation, training (e.g., computer-aided and real-world training) and operational settings.